ccna zero to hero

ccna zero to hero.A good practice is to mark the MAC address of each switch in the network topology schematic. This will make it much easier to troubleshoot a loop-causing failure and determine if a new switch added to the topology is the culprit of the loop. The exam requires confirmation that all switches are running either 802.M or 802.lw (RSTP), preferably the latter. To do this, use the command show spanning-treeo Additionally, confirm that the switch is the root switch in the VLAN.Layer 2 RedundancyFor the content presented in this chapter, the Cisco exam focuses on concepts rather than configuration. Be sure to familiarize yourself with Cisco's three-layer hierarchy model because the schematics on the exam may use it. Understand the three problems caused by Layer 2 loops (multiple frame copies, broadcast storms, and failure to properly learn MAC addresses) and the problems they cause.Spanning Tree ProtocolUnderstand how STP works: how the root switch is elected, how the root port and designated ports are selected, and the various states the ports may be in. You may encounter questions on the exam where you select answers related to these functions based on the diagram. Read the "Simple STP Example" section over and over again until you know the STP terminology and how it works. Remember that the switch ID consists of the switch's priority and MAC address. Familiarize yourself with how long a port lasts in various 802. Understand which scenario PortFast is best used for and what are the advantages of using PVST+ when implementing VLANs.Rapid Spanning Tree ProtocolsBe sure to familiarize yourself with the various RSTP port states: dropped, learned, and forwarded. RSTP configuration and optimization is not the focus of the exam.EtherChannelEtherChannel configuration is not the focus of the exam, but you need to understand what EtherChannels are and under what circumstances they are used.STP Troubleshooting Keep in mind the symptoms of a Layer 2 loop and be familiar with how to fix the configuration that causes a Layer 2 loop.